Aluminum soaps



Patented Dec. 2, 1952 ALUMINUM SOAPS Walter K. Dean, Ferguson, Mo., assignor to Mallinckrodt Chemical Works, St. Louis, Mo., a corporation of Missouri No Drawing. Application July 13, 1951, Serial No. 236,693

6 Claims. 1

This invention relates to aluminum soaps and more particularly to aluminum soap gelling agents.

Briefly, this invention is directed to aluminum soaps of organic acids consisting essentially of a major proportion of oleic acid and minor proportions of naphthenic and dimerized linoleic acids.

Among the several objects of this invention are the provision of aluminum soaps of the class described which can be dispersed in hydrocarbon fuels and solvents at room or only slightly more elevated temperatures; the provision of soaps of the type indicated which are substantially free from stickiness in the dry state; the provision of such soaps which gel hydrocarbon fuels and solvents at room temperature substantially more rapidly than soaps of similar types heretofore known; the provision of aluminum soaps of this class which form substantially firmer and less cohesive or stringy gels with mineral spirits than could be formed from similar soaps known heretofore; and the provision of such soaps which may be manufactured easily and economically from readily available starting materials. Other features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the products hereinafter described, the scope of the invention being indicated in the following claims.

While aluminum soaps capable of gelling mineral spirits at room temperature are known, these soaps have certain properties which limit their usefulness. For example, instead of being dry and free-flowing these known low temperature gelling agents tend to be sticky even in the dry state and, for that reason, relatively diflicult to manufacture and handle.

In accordance with the present invention, aluminum soaps are provided which do not possess these disadvantages but are dry and free-flowing, easily and economically manufactured, better able to gel hydrocarbon fuels and solvents at room temperatures more rapidly than previously known gelling agents, and which form firmer and les cohesive gels with mineral spirits which are more readily and completely broken in the presence of Water than known aluminum soaps. The gelling agents of the present invention are aluminum soaps of a mixture consisting essentially of oleic, naphthenic and dimerized linoleic acids, the oleic acid component being present in a major proportion, and the naphthenic and dimerized linoleic acids being present in a minor amount. In one of the preferred embodiments, the soap of this invention has the approximate composition:

Percent A1203 16.0 Oleic acid 67.0 Naphthenic acid 8.5 Dimerized linoleic acid 8.5

The aluminum content (calculated as A1203) may be varied between approximately 10% to 20% while the naphthenic and dimerized linoleic acid contents may each be varied preferably within the range of approximately 5% to 15%, the balance of the composition being substantially oleic acid. Such variations in the composition of these soaps do not significantly affect their major advantages.

The aluminum soaps of the present invention can be prepared by any of the methods customarily employed for the preparation of aluminum soaps. These novel aluminum soaps of this invention are used for gelling many hydrocarbon solvents such as, for example, chlorinated hydrocarbon solvents, benzene, toluene, xylene, gasoline, kerosene, mineral spirits, and some light oils. These hydrocarbon solvents can be gelled by mixing the soaps of this invention with the solvent at room temperature, Preferably, the mixture is stirred during the early stages of gelation so as to keep the soap in suspension, but stirring can be discontinued as soon as the viscosity becomes great ,enough to support the undispersed soap particles.

An important advantage possessed by gels made with the soaps of the present invention is the completeness and quickness with which these gels are broken in the presence of water. For example, in one method of treating oil wells with strong acids to increase their productivity, gelled kerosene, diesel fuel, Or crude oils are used to mask those areas of the well which are not to be acted upon by the acid. In such applications it is essential that the gel should be completely and quickly broken on completion of the treatment so that it will not thereafter interfere with normal operation of the well. Gels made according to the present invention are quite stable in the absence of water but they are quickly and completely broken in the presence of water.

The following examples illustrate the invention.

Example 1 A solution consisting of 60 grams of 50% sodium hydroxide solution in 2 liters of tap water was heated to a temperature of 90-95 C. by blowing steam through the solution. Then, 160 grams of oleic acid (having a titre less than 16-18 C.), 20 grams of dimerized linoleic acid and 20 grams of naphthenic acid (having a minimum acid number of 160 and containing less than 15% unsaponifiable material) were added. The mixture was stirred with a high speed stirrer for about twenty minutes so as to complete the saponification, sufficient cold tap water was added to cool the mixture to 65-70" C., and the amount of steam blowing into the solution was adjusted to maintain this temperature. Then 120 grams of 50% sodium hydroxide solution were added. Next, 250 grams of aluminum sulfate (Al2(SO4)a-18H2O), dissolved in 1.5 liters of tap water and warmed to 40-60 0., was gradually added to the vigorously stirred mixture over a period of approximately fifteen to twenty minutes. When precipitation was complete, a portion of the slurry was filtered, the filtrate was tested with methyl red indicator, and sulfuric acid or sodium hydroxide was added as required until the filtrate was acidic, but such that no more than 2 ml. of sodium hydroxide were required to neutralize 25 ml. of the filtrate. The slurry was then heated to 80-85 C. and stirred at this temperature for about thirty minutes until the soap was in a filterable condition. The soap slurry was then cooled, filtered on a suction funnel and washed with its own volume of water three or four times. As much of the wash water as possible was removed from the cake with suction. The cake was then dried overnight at 7 -90 C., crushed and sifted.

Example 2 Viscosity in Ccntipoises Time After Mixing Soap and Kerosene (Minutes) 0. over 16,000.

Example 3 A dispersion of parts by weight of the Example 1 soap in 95 parts by weight of kerosene was prepared as described in Example 2. The gel was heated to 60 C. in a water bath and held at this temperature for ninety minutes in order to insure complete dispersion of the soap. Water equivalent to 1% by weight of the composition was then beaten into the gel using a high-speed Viscosity in Time After Addition of Water (Minutes) centipoises When treated in this manner, the above gel was virtually completely broken after sixty minutes.

An important advantage of the soaps of this invention is their freedom from stickiness, which is a characteristic of prior-art soaps. Soaps of the present invention are dry and free-flowing and can be handled substantially more easily than similar soaps known heretofore. If desired, an antioxidant can be included in the compositions of this invention. It has been found, for example, that a-naphthol in concentrations usually less than 1% is useful for this purpose.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above products without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. An aluminum soap of a plurality of soapforming acids consisting essentially of a major proportion by weight of oleic acid and minor proportions by weight of naphthenic and dimerized linoleic acids, said minor proportions being not less than approximately 5%.

2. An aluminum soap of a plurality of soapforming acids consisting essentially of a major proportion by weight of oleic acid and minor proportions by weight of naphthenic and dimerized linoleic acids, said naphthenic and linoleic acids being present in approximately equal proportions, said minor proportions being not less than approximately 5%.

3. An aluminum soap of a plurality of soap forming acids consisting essentially of a major proportion by weight of oleic acid, approximately 5% to 15% by weight of naphthenic acid, and approximately 5% to 15% by weight of dimerized linoleic acid.

4. An aluminum soap of a plurality of soapforming acids consisting essentially of a major proportion by weight of oleic acid, approximately 8.5% by weight of naphthenic acid and approximately 8.5% by weight of dimerized linoleic acid.

5. A monobasic aluminum soap of a plurality of soap-forming acids consisting essentially of a major proportion by weight of oleic acid, approximately 5% to 15% by weight of naphthenic acid, and approximately 5% to 15% by weight of dimerized linoleic acid, the aluminum content calculated as A1203 being approximately 10% to 20% by weight.

6. A monobasic aluminum soap of a plurality of soap-forming acids consisting essentially of approximately 67% by weight of oleic acid, approximately 8.5% by weight of naphthenic acid, and approximately 8.5% by weight of dimerized The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Rosenbaum Apr. 1, 1930 Number 6 Name Date Miles Mar. 28, 1944 Sproule et a]. Feb. 12, 1946 Gebhart et a1 Mar. 11-, 1947 Ashley et a1. May 29, 1949 OTHER REFERENCES Ralston: text Fatty Acids and Their Derivatives, published 1948 by John Wiley and Sons, 10 Inc.. New York, N. Y., pp. 893-894, 937. 

1. AN ALUMINUM SOAP OF A PLURALITY OF SOAPFORMING ACIDS CONSISTING ESSENTIALLY OF A MAJOR PROPORTION BY WEIGHT OF OLEIC ACID AND MINOR PROPORTIONS BY WEIGHT OF NAPHTHENIC AND DIMERIZED LINOLEIC ACIDS, SAID MINOR PROPORTIONS BEING NOT LESS THAN APPROXIMATELY 5%. 